Removal and Installation of EGR Cooler and EGR Valve

9.Troubleshooting

See the troubleshooting section below to perform checking, countermeasures and to solve problems when any kind of problem occurs in the motor during operation. [1] Piston motor troubleshooting

Problem

The motor does not rotate

Motor rotation speed is insufficient

Motor rotation variation is high Possible cause Countermeasure and solution

There is an operation problem in a piece of equipment other than the piston motor or reduction gear. After investigating whether pressure is reaching the motor inlet side, investigate the causes of problems and countermeasures for each piece of equipment and perform inspection and repair.

If the cause is in the motor itself, there is dirt clogging an operation section or there is an operation problem.

Perform disassembly and clean and remove dirt from parts before reassembling the motor. If parts are damaged due to dirt, replace the parts. Motor inlet side pressure is low. Operate the main relief valve of the circuit and raise the set pressure.

There is abnormal wear on the sliding sections of the piston motor and pressurized oil is escaping.

Damage is occurring with the main parts of the piston motor. In this instance, abnormal noise is coming from the piston motor. The load on the piston motor is too large and the relief valve is operating. Perform disassembly and replace abnormally worn parts. After completely removing surface scratching, burrs, etc. and cleaning, perform reassembly. Perform disassembly and replace damaged parts. Perform reassembly after cleaning parts. Investigate the load conditions and adjust the load to an amount appropriate to the set pressure of the relief valve.

The cause resides in the hydraulic pump, pressure control valve, flow control valve, etc. Required oil flow is not being supplied to the piston motor and rotation is insufficient.

pressurized oil is moving from the highpressure side to the low-pressure side due to wear on the sliding sections of the piston motor (volume efficiency reduction), and speed is insufficient. After investigating whether the required flow is being supplied to the piston motor inlet side, investigate the causes of problems and countermeasures for each piece of equipment and perform inspection and repair. Perform disassembly, investigate the status of wear on the sliding sections of the piston motor, and perform repair and replacement according to the Maintenance Procedures.

There is looseness in the piston motor base plate fastening bolts. Internal leaking is increased and speed is insufficient. There is wear on the sliding sections of the piston motor and high-pressurized oil is leaking and flowing out from the drain port, which is causing speed to greatly decrease and causing rotation variation. When going down an incline, the double counter balance valve is causing hunting and rotation variation. Retighten the base plate fastening bolts to the specified torque.

Perform disassembly, investigate the status of wear on the sliding sections, and perform repair and replacement according to the Maintenance Procedures.

Perform disassembly, investigate the status of wear on the double counter balance valve, and perform repair and replacement according to the Maintenance Procedures.

Problem Possible cause Countermeasure and solution

Noise is high The shaft is touching driven parts due to problems with shaft core alignment, and this is producing noise. There is wear or damage on the piston motor bearing or damage has occurred with a spring, etc. and noise is being produced. Oil leaking There is looseness in bolts on matching surfaces, etc. and oil leaking is occurring. Oil leaking is occurring due to damage to oil seals, O-rings, packing, etc.

The amount of drain oil is high due to wear on the sliding sections of the piston motor, and oil leaking is occurring due to damage to the oil seals.

Cavitations is causing abnormal noise, rotation variation and pressure variation. Drain pressure has increased due to clogging in the drain line or because the drain line is long and thin, and this has damaged the oil seals and oil leaking is occurring. The amount of hydraulic oil in the hydraulic tank has decreased, and aeration is occurring due to tank taking in air.

Hydraulic oil within the motor lines and motor circuit is flowing out while hydraulic devices are turned off because the motor installation direction is inappropriate or the hydraulic tank position is inappropriate, and this is causing aeration to occur within the motor just after the motor is started.

Motor rotation stopped during operation When the motor is pumping, pressure on the motor inlet side becomes negative due to double counter balance valve operation problem and cavitation occurs. The load is too large and this caused the engine to stall. Seizing occurred in the sliding sections of the piston motor and the motor stopped rotating. Make the shaft core alignment accurate.

Perform disassembly and replace damaged parts such as bearings or springs. Perform reassembly after cleaning parts. Retighten the fastening bolts the specified torque. Perform disassembly and replace seals. Check the hydraulic oil temperature. When the temperature of the hydraulic oil is 80 ℃ or higher during operation, recheck the cooler and reduce the temperature of the hydraulic oil to below 80 ℃ . Perform disassembly, investigate the status of wear on the sliding sections, and perform repair and replacement according to the Maintenance Procedures. Replace oil seals. Perform reassembly after cleaning parts. Perform disassembly and replace oil seals. Perform drain line cleaning and remove foreign matter. Recheck lines and minimize resistance in line paths.

Check the amount of hydraulic oil in the hydraulic tank, and crisply with hydraulic oil according to the instructions on the machine main unit.

Check the motor installation direction and correct it. Check that the oil surface within the hydraulic tank is above the motor, and either modify it so that it is above the motor or set up a self-supply circuit so that the insides of the motor circuit and lines are fully supplied with oil before driving. Perform disassembly and perform repair and replacement according to the double counter balance valve Maintenance Procedures.

Check the load conditions and change the load to an appropriate amount. Investigate specifications values (especially flow amount and motor speed). If the motor speed has exceeded the upper limit, lower the flow amount. It is not possible to reuse the inside of the motor, so the motor should be replaced.

[2] Parking brake troubleshooting

Problem

The motor rotates if it is stopped with an external load acting on the motor. Possible cause

Parking brake torque has decreased due to disk wear.

The disk surface has been altered due to contact errors, etc., and the parking brake torque has decreased. The spring is worn or damaged and the parking brake torque is reduced.

Motor drive force is not being produced. Motor is heating up to an abnormal degree The external load is too large and the parking brake capabilities are insufficient. O-rings are damaged and pressurized oil is escaping, so the parking brake cannot be released.

Foreign matter is clogging the orifice inside the parking brake release oil path and pressurized oil is not reaching the parking brake cylinder chamber, which prevents the parking brake from being released. Drain pressure has increased due to clogging in the drain line or because the drain line is long and thin, and this has increased drain pressure and the parking brake cannot be released. Countermeasure and solution

Perform disassembly and replace the parking brake disk. Perform reassembly after cleaning parts. Perform disassembly and replace the disk. Also, repair the surface of the disk companion parts and perform reassembly. Perform disassembly and replace the spring. Perform reassembly after cleaning parts. Check the external load and change the load to an appropriate amount. Perform disassembly and replace the Orings. Perform reassembly after cleaning parts. Perform disassembly and remove foreign matter from the orifice. Perform reassembly after cleaning parts. Also, flush the inside of the line.

Clean the drain line. Also, recheck the line system and minimize resistance in the line path.

[3] Relief valve troubleshooting

Problem

The motor does not rotate or motor rotation is slow.

The motor does not stop or stopping is slow.

Shock at stopping is high Possible cause

There is foreign matter caught between the poppet seat and poppet on the relief valve, which is causing seating problems, and high-pressurized oil is leaking to the lowpressure side. The relief valve spring is damaged and high-pressurized oil is leaking to the lowpressure side. The relief valve spring is worn and the set pressure is decreased, which causes the relief to operate at low pressure. There is foreign matter caught in the seat section of the free piston and base plate of the relief valve, and the set pressure decreasing. There is foreign matter clogging the orifice set in the poppet of the relief valve, and the set pressure has decreased. There is foreign matter caught in between the poppet seat and poppet on the relief valve, which is causing seating problems, and the relief valve will not close. Countermeasure and solution

Perform disassembly and remove foreign matter. Perform reassembly after cleaning parts.

Replace the relief valve. Disassemble the motor and reassemble it after cleaning each part. Replace the relief valve.

Remove the relief valve and remove foreign matter.

Remove the relief valve and remove foreign matter.

Perform disassembly and remove foreign matter. Perform reassembly after cleaning parts.

The relief valve spring is damaged and the relief will not close.

The relief valve spring is worn and the set pressure has decreased, which has caused the brake force to decrease. Replace the relief valve. Disassemble the motor and reassemble it after cleaning each part. Replace the relief valve.

There is foreign matter caught in the seat section of the free piston and base plate of the relief valve, and the set pressure and brake force have decreased.

There is foreign matter clogging the orifice set in the poppet of the relief valve, and the set pressure and brake force have decreased. Remove the relief valve and remove foreign matter.

Remove the relief valve and remove foreign matter.

There is foreign matter caught in the sliding section of the poppet and the poppet is not moving. Replace the relief valve.

There is foreign matter caught in the free piston and the piston is not moving.

Remove the relief valve and reassemble after removing foreign matter. The relief set pressure is too high. Replace the relief valve.